Various types of apparatus have been devised for assisting in the viewing of large quantities of flat objects, such as films, photographs, drawings, or printed material. The need for such apparatus for viewing x-rays is widely known and recognized, as described in U.S. Pat. Nos. 3,246,412; 3,362,094; and 2,002,807, which are hereby incorporated by reference in their entirety into the present application.
A good deal of prior art exists merely in the types of frames, mounts, or assemblies for holding documents such as x-ray films to facilitate viewing. Much of that prior art, however, is specifically directed to frames or mounts designed to hold a plurality of films, with each film having the same basic dimensions. Examples of such prior art may be found in U.S. Pat. Nos. 3,559,320; 3,347,134; 3,336,690; 2,842,882; 3,981,092; 2,234,427; 3,831,301; 4,110,924; 4,112,165; and 4,146,985. Obviously, a good deal of effort has therefore been expended in providing a better frame or mount for assisting in the viewing of x-ray films.
With respect particularly to the apparatus or assemblies other than frames or mounts devised to assist in the viewing of x-rays, several patents generally depict such devices, but are in many respects dissimilar to the apparatus of the present invention. Such prior art apparatus may be relatively simple in design and construction, e.g., U.S. Pat. Nos. 4,118,654; 4,004,360; 3,896,603; 4,152,852; and 4,373,280, but such prior art apparatus is not well suited for viewing x-ray films on a large scale basis, and particularly when such films are of different dimensions. On the other hand, prior art apparatus may be complex in design and construction, e.g., U.S. Pat. Nos. 3,359,669 and 3,201,883, and thus such apparatus has not been widely accepted in the industry. Devices have been also patented for viewing x-ray film which utilize a magazine to move the x-rays past a stationary light source. Examples of assemblies utilizing the movable magazine concept are U.S. Pat. Nos. 3,246,412 and 3,541,711.
The prior art also includes U.S. Pat. Nos. 3,362,094; and 2,002,867, which are directed to the concept of mounting x-rays on a plastic strip or sheet, and then rolling and unrolling such plastic in the manner of a scroll to pass the x-rays past a viewing station. Both of these latter patents are directed to such assemblies, and include upper and lower rollers for holding the plastic sheet so that the x-rays can be moved in a generally vertical direction to pass by the viewing area.
The need exists for improved apparatus for efficiently viewing a plurality of x-rays, wherein particular x-rays can be easily and quickly added or removed from the viewing device. Much of the prior art apparatus requires too much time and difficulty to add or remove particular x-rays from the veiwing machine.
The apparatus of the prior art is also generally not well adapted for mass viewing of x-rays having various sizes or dimensions. In many instances, the radiologist desires to simultaneously view a number of x-rays, and the x-rays have been obtained from different machines which produce x-rays of different sizes, or certain x-rays have been reduced or enlarged. Many of the prior art assemblies referred to above are either incapable of viewing various size x-rays or are not well suited for viewing x-rays of different sizes.
When viewing x-rays, radiologists often prefer to have x-rays moving horizontally or laterally across the viewing area rather than vertically. Also, apparatus exists in the prior art for viewing x-rays placed on an elongate sheet of plastic adapted for moving in the horizontal direction, but such apparatus commonly also employs guide wires or elastic bands which run across the x-rays and thus detract from the clarity of the entire x-ray.
The disadvantages of the prior art are overcome by the present invention, and improved methods and apparatus are provided for viewing documents such as x-rays which can be mounted on a transparent sheet of plastic which is horizontally movable across a viewing area. The present invention is particularly well adapted for use with apparatus comprising a pair of drums on either side of the viewing area so that the sheet of plastic with the x-rays can be unrolled from one drum while simultaneously rolled on another drum as the sheet of plastic passes the viewing area.